Life On Earth Laboratory Manual for Biological Science 10

Biological Science 10: Principles of Biology
Monday and Wednesday 14:30-16:00 SS214
Instructor: John Crocker
Email: jcrocker@gavilan.edu
Office: LS117
Office Hours: Monday 13:30-14:30 or by appointment
Required Texts:
Audesirk, Audesirk & Byers Life On Earth
Pearson Custom Publishing-Gavilan College.
Laboratory Manual for Biological Science 10
Gavilan College. (hhh.gavilan.edu/jcrocker)
Course Goals:
1. Think critically about facts and issues in science.
2. Describe key characteristics of all living things
3. Describe essential biological structures and processes
that occur at the molecular, cellular, and organismal
levels that enable life.
4. Explain gene function and the role of genes in
inheritance and evolution.
5. Explain and practice the scientific method of inquiry.
6. Describe ecological interactions that occur within
ecosystems, communities, and populations.
7. Recognize biological processes in your daily life.
8. Effectively organize and present information to a group
Grading Policy:
Lecture (70%):
Laboratory (30%)
3 exams at 100 points each (drop 1)
Homework/Quizzes
Final Exam
55%
10%
35%
Lab reports/ presentations
Lab Quizzes
60%
40%
A= 90% and up (A-=89.5)
B= 80-89% (B+88; B-79.5)
C= 70-79% (C+=78)
D= 60-69%
F= less than 60%
NRS= withdrawal during weeks 1-5
W= withdrawal during weeks 6-14
F= failure to notify instructor of withdrawal or
withdrawal after week 14
I= incomplete (for unforeseen and justifiable reasons, or
emergency; may be granted only after week 14
-Please note that this point system is tentative and may change slightly.
-As per college policy, students missing one more class hour than the unit value of the course may be
dropped. (However, it is your responsibility to drop the class (either through admissions, in person or
by telephone.) You are responsible for all material covered in class. If you foresee missing more than
one or two days of class, please inform me.
-Students requiring special services or arrangements because of hearing, visual, or other disability should
contact their instructor, counselor, or the Disability Resource Center
-Students are expected to exercise academic honesty and integrity. Violations such as cheating and
plagiarism will result in disciplinary action which may include recommendation for
dismissal. This further discussed in the Student Handbook. Expected conduct during examinations is
discussed in the last page of this handout.
Please take out pen or pencil and paper
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Define the term Biology.
What is the scientific method?
List the steps of the scientific method.
Define the term hypothesis.
Define the term theory.
List three evidences in support of the theory of evolution.
What are the common characteristics of all living things?
List the levels of organization of life beginning with the smallest and
progressing up in complexity to communities of multiple species.
What is DNA?
What is a species?
How are species classified?
The pictured organism is most closely related to
a) Sponges
b) Corals
c) Humans
d) Grey aliens
e) Nothing, I made it in Photoshop
Chapter 1
An Introduction to
Life on Earth
Lectures by
Gregory Ahearn
University of North Florida
Modifed by
John Crocker
Copyright © 2009 Pearson Education, Inc..
Why Study Biology?
 Biology helps you
understand your body.
 Biology helps you
become an informed
citizen.
 Biology can open career
opportunities.
 Biology can enrich your
appreciation of the world.
Scientific Principles
 Biology is a scientific discipline
 All scientific inquiry is based on a small set
of assumptions or principles
• Natural causality
• Uniformity in space and time
• Similar perception
Natural Causality

Historical approaches to studying life
1. Belief that some events happen through
supernatural forces (e.g. the actions of
Greek gods)
2. Belief that all events can be traced to
natural causes that we can comprehend
(natural causality)
• Corollary: Evidence gathered from
nature has not been deliberately
distorted to fool us
Uniformity in Space and Time
 Natural laws are uniform in space and time
 This principle is key understanding
biological events (e.g. evolution) that
occurred before humans recorded them
 Creationism is contrary to the principle of
uniformity-in-time and natural causality
• Creationists hold that different species were
created one at a time by the direct
intervention of a supernatural being
Similar Perceptions
 Assumption that all human beings
perceive natural events in fundamentally
the same way
 Common perception allows us to accept
observations of other humans as reliable
 Common perception is usually not found in
appreciation of art, poetry, and music, nor
between cultures or religious beliefs
• Value systems are subjective
• Science requires objectively gathered data
The Scientific Method
 Scientific inquiry is a rigorous method for
making observations
 The Scientific Method for inquiry follows 4
steps…
The Scientific Method
1. Observation of a phenomenon
– Subsequent development of questions
2. Formulation of a hypothesis
– A supposition that explains an observed
phenomenon and leads to testable
predictions
3. Testing through experimentation
– Additional controlled observations
4. Development of a conclusion
– Evaluation of hypothesis in light of
experimental data
The Scientific Method
 Scientific experimentation tests the
assertion that a single variable causes a
particular observation
 The experiment must rule out the influence
of other possible variables on the recorded
observations
 Controls are incorporated into
experiments
 Controls keep untested variables constant
 Scientific method is illustrated by
Francesco Redi’s experiment
Application to Everyday Problems

Assume you are late for an appointment
and hurriedly try to start your car
1. Observation: The car won’t start
Application to Everyday Problems
2. Hypothesis: the battery is dead
Application to Everyday Problems
3. Experimental design: Replace your
battery with another and restart the
car
Application to Everyday Problems
4. Premature conclusion:
• The problem was a dead battery
because the car starts when
replaced with a different one
Application to Everyday Problems
5. Recognition of inadequate controls
• Did you attempt to start the car
more than once?
• Was the battery cable on my
original battery loose?
Application to Everyday Problems
6. Establishing a control
a. Reinstall your old battery, check for
tight cables, now try to start the car
b. If car still fails to start on old battery,
the only variable in this
investigation now is the
effectiveness of the battery
Application to Everyday Problems
7. Making a better conclusion, based
on controlled experiments
• Your battery was probably dead
 Question: Have all other variables been
eliminated?
• Example: loose battery cables
• Example: broken electrical wires
 Solution: Control for other variables
• Make sure cables are tight.
• Make sure electrical wires are in good
condition.
Limitations of the Scientific Method
 Can never be sure all untested variables
are controlled
 Conclusions based on the experimental
data must remain tentative
 Results of experimentation must be
communicated thoroughly and accurately
to other scientists for repetition
 Repetition by other scientists add
verification that findings can be used as
the basis for further studies
Science Is a Human Endeavor
 Human personality traits are part of “real
science”
 Scientists, like other people may be driven
by pride, ambition, or fear
 Scientists sometimes make mistakes
 Accidents, lucky guesses, intellectual
powers, and controversies with others
contribute strongly to scientific advances
Science Is a Human Endeavor
1. In the 1920s, bacteriologist Alexander
Fleming grew bacteria in cultures
2. One of the bacterial cultures became
contaminated with a mold
3. Fleming nearly destroyed the culture
when he noticed the mold (Penicillium)
inhibited bacterial growth in the culture
4. Fleming hypothesized that the mold
produced an antibacterial substance
Science Is a Human Endeavor
 Penicillin kills bacteria.
A petri dish
contains solid
growth medium
Bacteria grow in
a pattern created
by streaking
A substance from
the mold diffuses
outward and inhibits
the growth of
nearby bacteria
A colony of the
mold Penicillium
Fig. 1-7
Science is a Human Endeavor
5. Further tests using broth from pure
Penicillium cultures lead to the discovery
of the first antibiotic, penicillin
6. Fleming continued beyond a lucky
“accident” with further scientific
investigation to a great discovery
7. “Chance favors the prepared mind”
(Louis Pasteur)
Scientific Theory
 A scientific theory differs in definition
from that of everyday usage
• Many people use the word theory to mean
hypothesis, and “educated guess”
Scientific Theory
 A scientific theory is a general explanation
for important natural phenomena
• It is extensively and reproducibly tested
• It is more like a principle or natural law (e.g.
the atomic, gravitational, and cell theories)
• If compelling evidence arises, a theory may
be modified
Scientific Theory
 New scientific evidence may prompt
radical revision of existing theory
 Example: the discovery of prions…
Scientific Theory
 Before 1980, all known infectious diseases
contained DNA or RNA
 In 1982, Stanley Prusiner showed that the
infectious sheep disease scrapie is caused
by a protein (a “protein infectious particle”
or prion)
Scientific Theory
 Prions have since been shown to cause
“mad cow disease” and diseases in
humans
 The willingness of scientists to revise
accepted belief in light of new data was
critical to understanding and expanding
the study of prions
Science Is Based on Reasoning
 Inductive Reasoning
• A generalization is created from many
observations
• Used in the development of scientific
theories
• e.g., the cell theory (all living things are
made of one or more cells) arises from many
observations that all indicate a cellular basis
for life
Science Is Based on Reasoning
 Deductive Reasoning
• Generating hypotheses based on a wellsupported generalization (such as a theory)
• e.g., based on the cell theory, any newly
discovered organism would be expected to
be composed of cells
1.2 How Do Biologists Study Life?
 Life can be studied at different levels of
organization.
cell
nerve cell
tissue
nervous tissue
organ
brain
organism
pronghorn antelope
population
herd of pronghorn antelope
community
snakes, antelope, hawks, bushes, grass
Fig. 1-5
1.3 What Is Life?
 Characteristics of living things
• Living things are organized.
Fig. 1-8
1.3 What Is Life?
 Characteristics of living things
• Living things are complex
Fig. 1-8
1.3 What Is Life?
 Characteristics of living things
• Living things are organized and complex.
Fig. 1-8
1.3 What Is Life?
 Characteristics of living things
• Living things grow and reproduce.
Fig. 1-9
1.3 What Is Life?
 Characteristics of living things
• Living things respond to stimuli
• Light
• Sound
• Chemicals
• Hunger
• Pain
• Touch
• Heat
• Cold
• Motion
• Gravity
1.3 What Is Life?
 Characteristics of living things
• Living things acquire and use material and
energy.
Fig. 1-10
1.3 What Is Life?
 Characteristics of living things
• Living things use DNA to store information.
Fig. 1-11
1.4 Why Is Life So Diverse?
 DNA: The universal molecule of life
• DNA is found in the bodies of all organisms,
from bacteria to whales.
• Its universal presence suggests that all
organisms have descended from a common
ancestor having the same molecule.
• DNA is passed from generation to generation
during periods of reproduction.
• Organism diversity results from small changes
in DNA accumulating over billions of years of
evolution.
1.4 Why Is Life So Diverse?
 Life’s unity and diversity is a result of
evolution.
• Life changes over long periods of time.
• Groups of organisms change from generation
to generation.
• The changes that accumulate in populations
of organisms over time is called evolution.
• Life’s unity arises from the fact that diverse
descendents arise from single ancestors.
• The unifying principle of biology is that all of
life’s features in today’s organisms arose
through evolution.
1.4 Why Is Life So Diverse?
 Natural selection is the basis of evolutionary
change.
• Characteristics of individuals in a group vary.
• Some characteristics help individuals survive
and reproduce.
• Those that reproduce pass on these traits to
future generations.
• The favored traits are accumulated in
populations over time, changing the
individuals within the group.
• Example: Big teeth in beavers favor survival
and are passed on to future generations.
1.4 Why Is Life So Diverse?
 Biodiversity is threatened by human
activities.
• Biodiversity is the wealth of species in the
world and the interrelationships that sustain
them.
• Human expansion in the world has severely
reduced habitats for these interrelationships to
flourish.
• Extinction of many organisms have followed
from the growth of human populations on all
the world’s continents.
• Pollution and chemical wastes kill aquatic
organisms.